[gorena]

It defeats the grocery store tracking mentioned in the parent post - Apple Pay uses a different temporary credit card number for each transaction, so the store can't track you with it.

I'm not sure what the server side component is - but I don't believe they would have itemized data. So Apple/Amex know that you go to Whole Foods, but don't know what you're buying. Obviously, credit card companies have always had that data anyways.